The present invention relates to methods and apparatus for irrigating the gastrointestinal tract or portions thereof.
The importance of a clean colon to the success of colonic surgery has been well established. This type of surgery is still plagued with septic complications, most of which arise from endogenous intestinal bacteria that contaminate the operative field during the surgical procedure. Surgeons have learned that they can significantly reduce the chances that a patient will develop a wound infection, intraabdominal sepsis, or an anastomotic dehiscense, following surgery if the colon has been effectively cleansed before the bowel wall is violated.
Some controversy exists as to the best method of bowel preparation for patients who undergo surgery of the colon. Many regimens of mechanical and antimicrobial preparations have been developed to reduce the concentration of colonic bacteria below critical levels.
The most widely used method of preparing the bowel for surgery comprises dietary restrictions to clear fluids, laxatives, enemas and one of multiple antibiotic combinations administered orally on the day prior to surgery. Many devices have been designed for the efficient administration of enemas. All such devices force fluid through the bowel in a retrograde direction in a repeating sequence and rely on peristalsis to flush out the irrigant and colonic waste. Such bidirectional flow renders the process slow and inefficient due to the fact that contaminants are washed back and forth within the bowel. The degree to which the bowel can be cleaned by such prior devices is therefore severely limited.
The conventional technique for bowel preparation as described above has many disadvantages. It achieves suboptimal cleansing and must be restricted to elective cases. Administration is highly variable and is distressing to the patient. It prolongs hospital confinement and causes nutritional deprivation. It promotes the development of antibiotic resistant intestinal flora and has adverse metabolic effects. The antibiotics employed can be toxic. Preparation of the patient requires a significant labor investment by hospital staff and can be wasteful and even harmful should surgery be cancelled or postponed. Furthermore, preparing a patient for colonic surgery in the conventional manner entails considerable expense.
In order to avoid some of the disadvantages of conventional bowel cleansing techniques as described above, an alternative method has been recently developed, sometimes referred to as "whole bowel irrigation." According to this technique, on the day prior to surgery a large volume of irrigating fluid is administered to the patient either by mouth or by way of a nasogastric tube, at a rate which exceeds the capacity of the gut to absorb the irrigant. The unabsorbed fluid washes the colon as increased peristaltic activity flushes it through and out the rectum. Although this technique may shorten hospitalization, it also suffers from certain serious disadvantages. In particular, cleansing is still suboptimal. Fluid overload and electrolyte imbalance may be produced and the procedure is therefore contraindicated in those patients having cardiac, renal, or hepatic problems. This technique is also distressing to patients, causing nausea and vomiting on occasion, and also requires substantial labor investment by the hospital. Variations of this procedure, such as catharsis induced by ingestion of oral mannitol, have been attempted but suffer similar or other disadvantages.
Despite the variety of preoperative bowel cleansing techniques in use, none give uniformly good results. A large percentage of patients prepared for elective colonic surgery are found at laparotomy to have a fair degree of fecal loading. Those patients operated on emergently invariably have unclean bowel. To deal with a bowel loaded with feces encountered at surgery several methods of intraoperative bowel preparation have been devised.
Instillation of antimicrobial agents into the bowel lumen prior to enterotomy has been suggested. See, for example "Intestinal Antisepsis" by Edgar J. Poth, M.D., American Journal of Surgery, Vol. 88, Nov., 1954; "Experimental Evaluation of `Instant` Preparation of the Colon with Povidone-Iodine" by Frank E. Jones, M.D., Jerome J. DeCosse, M.D., and Robert E. Condone, M.D., Surgical Clinics of North America, Vol. 55, No. 6, Dec., 1975; and "Bacteriologic and Systemic Effects of Intraoperative Segmental Bowel Preparation with Povidone Iodine," by Arango et. al., Archives of Surgery, Vol. 114, Feb., 1979. However, these methods fail to remove the fecal matter, which cannot be completely sterilized. When the bowel is incised or opened virulent material can still escape, infect the parietes, and soil and obscure the anastomotic field.
Intraoperative irrigating techniques have also been suggested. See for example "Safety in Colonic Resection," by Edward G. Muir, Proceedings of the Royal Society of Medicine, Vol. 61, Apr. 1968; and "Intraoperative Irrigation of the Colon to Permit Primary Anastomosis," by H. A. Dudley, A. G. Radcliffe, and D. McGeehan, British Journal of Surgery, Vol. 67, 1980. These techniques, however, are clumsy, may easily result in spillage of bowel contents and peritoneal contamination, leave significant amounts of fecal material in the bowel, and do not affect the concentration of bacteria within the remaining feces. Some intraoperative irrigating techniques (see, e.g., "Colonic Decompression and Lavage in Anterior Resection of the Rectosigmoid," by H. Clay Alexander, Surgery, Obstetrics, and Gynecology, Vol. 135, 1972; and "Intraoperative Chaffin Sump Recto-Colonic Irrigation" by G. Bruce Thow, M.D., Diseases of the Colon and Rectum, Vol. 19, No. 4, May-June, 1976) amount to little more than intraoperative enemas.
Others have suggested combining both irrigation and antimicrobials. However, such techniques are c1umsy and cannot accomodate high volumes of irrigant at high rates of flow. (See, e.g., "Impromptu Bowel Cleansing and Sterilization," by Marvin L. Gliedman et. al., Surgery, Vol. 43, No. 2, Feb., 1958).
Whenever unidirectional antegrade irrigation has been employed, an enterotomy for placement of a proximal irrigating catheter was performed, exposing the operative field to a risk of contamination even before cleansing was begun.
Thus, an improved method for intraoperative bowel preparation which can cleanse the colon so safely, effectively, and quickly, that it could be recommended for routine use in elective cases as well as in emergency laparotomies, would be of great value.